Stock-Based Compensation - Additional Information (Detail)	12 Months Ended
Dec. 31, 2018
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock options and restricted stock	3 years
Contractual terms	10 years
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock options and restricted stock	4 years
Restricted Stock [Member] \| Minimum [Member] \| Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock options and restricted stock	3 years
Restricted Stock [Member] \| Minimum [Member] \| Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock options and restricted stock	1 year
Restricted Stock [Member] \| Maximum [Member] \| Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock options and restricted stock	4 years
Restricted Stock [Member] \| Maximum [Member] \| Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock options and restricted stock	3 years

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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